Brake-operating mechanism



Jan. 25, 1927.

J C. SMITH BRAKE OPERATING MECH ANISM Filed March 2. 1926 JwuentocPatented Jan. 25, 1927.

UNITE STATES J "CLIFFORD SMITH, OF BELLE-LOWER, CALIFORNIA.

BRAKE-OPERATING MECHANISM.

Application filed' March 2, 1926.

'* anisms.

In well drilling rigs, the calf wheel is driven by an engine and isemployed for lowering and raising tools in the well. These calfwheelsare controlled by a band brake operated-from a lever and often,due

to sudden reversal of the engine, an unexpected engagement of the clutchor a sudden releasing of the weight which supported from the calf wheel,this lever will suddenly shift with the result that a workman is manytimes injured thereby. The probability of such injury occurring will berealized when it is noted that it is necessary to have a workman inconstant attendance upon the lever during drilling operations.

A further object of the invention is to produce a device of thischaracter which may be applied to the operating levers of calf wheelbrakes which are now in position upon the rig.

A further object of the invention is to provide adjustable means forcontrolling the position of the calf wheel brake with rela-- tion to therimof the calf wheel.

These and other objects I attain by the construction shown in theaccompanying drawings, wherein for the purpose of illustration is showna preferred embodiment of my invention and'wherein Figure 1 is a sideelevation showing brake operating mechanism constructed in accordancewith my invention, the control pawl being indicated in normal positionby solid lines;

Figure 2 is a plan view of the brake operating mechanism detached;

Figure 3 is a sectional view showing the manner of connecting the cablewith the brake lever.

Referring now more particularly to the drawings, the numeral generallydesignates the calf wheel of well drilling apparatus, the calf wheelbeing rotatably mounted and having secured thereto the usual drum 11upon which the tool cable 12 is wound. The numeral 13 generallydesignates a flexible brake band co-operating with the rim of the calfwheel and having one end thereof secured to a rigid support 14 while theopposite end thereof is secured to the crank 15 of a crank shaft 16mounted in suitable is applied thereto.

Serial No. 91.785.

bearings 17 upon the support 1 1 or upon the floor of the derrick. Oneend of this shaft has rigidly secured'thereto an operating lever 18. Thecrank shaft 16 and lever 18 are usuallly produced from a single bar ofround metal bent in the proper form. It will be obvious that byoscillating the lever 18, the band 13 may be engaged with or disengagedfrom the periphery of the calf wheel.

In order to limit the separation of the brake band 13 from the peripheryof the drum, I provide a limiting element consisting of a rod or cable19 rigidly securedat one end to a suitable support 20 which passes aboutand is substantially co-extensive with the band 13. The opposite end ofthe limiting element 191s adjustably secured, as at 21, to a support 22arising from the floor of the derrick. By adjusting this limiting band,the space between adjacent faces of the calf wheel and band may be atall times maintained uniform,- regardless of wear to which the band 13is subjected. The connection of the brake band 18 with the crank ispreferably likewise made adjustable so that any extreme slack occurringin the brake band may be removed and accordingly the necessary movementof the lever 18 to apply the band kept within certain limits.

In accordance with my invention, 1 further provide an operatingmechanism for the band including a shaft 24 mounted in suitable bearings25 and 26 arising from the floor of the derrick. Between the bearings 25and 26 a drum 2'? is secured to the shaft and at one end of the shaft ahand wheel 28 Adjacent the hand. wheel, the shaft is formed with aratchet29 and the adjacent bearing 25 has pivoted thereto a dog 30 forcoaction with the ratchet. This dog is connected by a link 31 with afoot treadle 32, the connections and construction of the various partsbeing such that the dog normally assumes an inoperative position but maybe engaged with the ratchet by application of pressure to the foottreadle. A cable or the like is wound several times about the drum andis trained about a pulley or pulleys 83 and between the ends of thecable is inserted a sleeve 34 which slidably embraces the lever 18intermediate the ends thereof and adjacent its free end.

In the use of the device, when it is desired to apply the brake, thehand wheel is rotated to the left. This forces the lever 18 downwardlythrough the sleeve 34- in the direction of the arrow with the resultthat the brake band is tightened upon the periphery of the calf wheel.hen the brake band has been tightened, the pawl may be engaged with theratchet by placing the foot upon the foot treadle and after the pawl isengaged, the tendency of the brake to release will keep a constantstrain of the ratchet teeth against the pawl so that this engagement ismaintained. Any tendency of the lever to kick will be frustrated by theengagement of the sleeve therewith and the operator is enabled to leavethe lever to assist in other work about the derrick. When it is desiredto release the lever, the wheel is rotated in a direztion to tighten thesame for a suliicient distance to release the pawl which moves to itsinoperative position, thus permitting the wheel to be reversed and thebrake to be released.

It will, of course, be obvious that the construction hereinbefore setforth is capable of a certain range of change and modification withoutmaterially departing from the spirit of the invention and I accordinglydo not limit myself to such specific structure except as hereinafterclaimed.

I claim z- 1. In combination, a calf wheel brake band and an operatinglever for shifting the same, a drum, a cable wound upon the drum andtrained through a suitable pulley, a sleeve with opposite sides of whichthe ends of the cable connect, said sleeve slidably embracing the leverand means for locking the drum against rotation in a direction permitting movement of the lever to release the band.

2. In combination, a calf wheel brake hand and an operating lever forshifting the same, a drum, a cable wound upon the drum and trainedthrough a suitable pulley, a sleeve with which the ends of the cableconnect slidably embracing the lever and means for locking the drumagainst rotation in a direction permitting movement of the lever torelease the band, said means being normally inoperative and upon apredetermined operation of the drum releasing the drum to permitrotation thereof in a direction releasing the lever.

3. In combination, a calf wheel brake band and an operating lever forshifting the same, a drum, a cable wound upon the drum and trainedthrough a suitable pulley, a sleeve with which the ends of the cableconnect slidably embracing the lever, a ratchet associated with thedrum, a normally inoperative pawl for engaging the ratchet to preventrotation of the drum in a direction permitting movement of the lever torelease the band and means for shifting said pawl into engagement withthe ratchet.

4. In combination, a calf wheel. a brake band therefor and an operatinglever for shifting the brake band, a drum a cable wound upon the drumconnections between opposite ends of the cable and opposite sides of theoperating lever for shifting the operating lever in opposite directionsand means for rotating the drum.

5. In con'ibination, a calf wheel, a brake band therefor and anoperating lever for shifting the brake band, a drum, a cable wound uponthe drum, connections between opposite ends of the cable and oppositesides of the operating lever for shifting the operating lever inopposite directions and means for locking the drum against rotation in adirection permitting movement of the lever to release the band.

6, In combination, a calf wheel, a brake band therefor, an operatinglever for the brake band swinging in a given plane, a sleeve slidablyengaging the lever, means connected with the sleeve for positivelyshifting the sleeve in opposite directions to thereby operate the brakelever, said means including a rotatable operator actuated element remotefrom the plane of swing of the lever and means for locking the firstnamed means against movement in one direction.

In testimony whereof I hereunto atlix my signature.

J CLll FORl) SMITH.

